/*
 * MIT License
 *
 * Copyright (c) 2023 北京凯特伟业科技有限公司
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in all
 * copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */
package com.je.bpm.engine.impl.delegate;

import com.je.bpm.engine.delegate.DelegateExecution;
import com.je.bpm.engine.delegate.Expression;
import com.je.bpm.engine.impl.bpmn.parser.FieldDeclaration;
import java.util.*;

import static java.util.Collections.unmodifiableMap;

public class BpmnMessagePayloadMappingProvider implements MessagePayloadMappingProvider {

    private final List<FieldDeclaration> fieldDeclarations;

    public BpmnMessagePayloadMappingProvider(List<FieldDeclaration> fieldDeclarations) {
        super();
        this.fieldDeclarations = fieldDeclarations;
    }

    @Override
    public Optional<Map<String, Object>> getMessagePayload(DelegateExecution execution) {
        Map<String, Object> payload = new LinkedHashMap<>();

        fieldDeclarations.stream()
                .map(field -> applyFieldDeclaration(execution,
                        field))
                .forEach(entry -> payload.put(entry.getKey(), entry.getValue()));

        return Optional.of(payload)
                .filter(map -> !map.isEmpty())
                .map(map -> unmodifiableMap(map));
    }

    protected Map.Entry<String, Object> applyFieldDeclaration(DelegateExecution execution, FieldDeclaration field) {
        return Optional.of(field)
                .map(f -> {
                    Object value = Optional.ofNullable(f.getValue())
                            .map(v -> (Expression.class.isInstance(v))
                                    ? Expression.class.cast(v).getValue(execution)
                                    : v)
                            .orElse(null);

                    return new AbstractMap.SimpleImmutableEntry<>(field.getName(), value);
                })
                .get();
    }
}
